Treatment with methotrexate blocks the folate pathway and causes defects during embryogenesis in vertebrates. In humans, a lack of folate during pregnancy can lead to development of neural tube defects. In zebrafish development, methotrexate blocks embryo development at the stage of early somite formation. Which of the following events would also be blocked by methotrexate treatment of zebrafish embryos if development stops early in the stage of somite formation?(more than 1)
A.movement of cells of external layer into the interior to eventually form the gut cavity
B.epiboly
C.eye development
D.internalization of yolk into the developing gut cavity